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authorEric Dumazet <edumazet@google.com>2024-01-18 20:17:49 +0000
committerDavid S. Miller <davem@davemloft.net>2024-01-21 18:09:30 +0000
commita54d51fb2dfb846aedf3751af501e9688db447f5 (patch)
treea7caec9bea91b6523352babace79103a93c5b514 /net/core/sock.c
parente3f9bed9bee261e3347131764e42aeedf1ffea61 (diff)
udp: fix busy polling
Generic sk_busy_loop_end() only looks at sk->sk_receive_queue for presence of packets. Problem is that for UDP sockets after blamed commit, some packets could be present in another queue: udp_sk(sk)->reader_queue In some cases, a busy poller could spin until timeout expiration, even if some packets are available in udp_sk(sk)->reader_queue. v3: - make sk_busy_loop_end() nicer (Willem) v2: - add a READ_ONCE(sk->sk_family) in sk_is_inet() to avoid KCSAN splats. - add a sk_is_inet() check in sk_is_udp() (Willem feedback) - add a sk_is_inet() check in sk_is_tcp(). Fixes: 2276f58ac589 ("udp: use a separate rx queue for packet reception") Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/sock.c')
-rw-r--r--net/core/sock.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/net/core/sock.c b/net/core/sock.c
index 158dbdebce6a..0a7f46c37f0c 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -107,6 +107,7 @@
#include <linux/interrupt.h>
#include <linux/poll.h>
#include <linux/tcp.h>
+#include <linux/udp.h>
#include <linux/init.h>
#include <linux/highmem.h>
#include <linux/user_namespace.h>
@@ -4144,8 +4145,14 @@ bool sk_busy_loop_end(void *p, unsigned long start_time)
{
struct sock *sk = p;
- return !skb_queue_empty_lockless(&sk->sk_receive_queue) ||
- sk_busy_loop_timeout(sk, start_time);
+ if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
+ return true;
+
+ if (sk_is_udp(sk) &&
+ !skb_queue_empty_lockless(&udp_sk(sk)->reader_queue))
+ return true;
+
+ return sk_busy_loop_timeout(sk, start_time);
}
EXPORT_SYMBOL(sk_busy_loop_end);
#endif /* CONFIG_NET_RX_BUSY_POLL */